CODE
128 SYMBOLOGY

CODE 128 INTRODUCTION

Code 128
is a alphanumeric symbology. Code 128 symbology must include
a checksum digit.Code 128 has three character Set: A,B,C.Three
different start characters tell the reader the character set used
in the following encoding, and three shift codes permits changing
character set inside the symbol. From the table below, we can
see that character set A and B is used to encode alpha-numeric
information while character set C offers double density when being
used to encode numeric data. The special character Shift, changes
the character set of the immediately followed character. The shift
work only with Code A or Code B characters. Four FNC characters
are listed, FNC2 is used to tell barcode reader to store the data
and transmit with next symbol; FNC1, FNC3 and FNC4 are reserved
for future applications.Encoding Table as follow:

VALUE

CHARACTER
SET

VALUE

CHARACTER SET

A

B

C

A

B

C

00

SP

SP

00

53

U

U

53

01

!

!

01

54

V

V

54

02

"

"

02

55

W

W

55

03

#

#

03

56

X

X

56

04

$

$

04

57

Y

Y

57

05

%

%

05

58

Z

Z

58

06

&

&

06

59

[

[

59

07

'

'

07

60

\

\

60

08

(

(

08

61

]

]

61

09

)

)

09

62

^

^

62

10

*

*

10

63

_

_

63

11

+

+

11

64

NUL

`

64

12

,

,

12

65

SOH

a

65

13

-

-

13

66

STX

b

66

14

.

.

14

67

ETX

c

67

15

/

/

15

68

EOT

d

68

16

0

0

16

69

ENQ

e

69

17

1

1

17

70

ACK

f

70

18

2

2

18

71

BEL

g

71

19

3

3

19

72

BS

h

72

20

4

4

20

73

HT

I

73

21

5

5

21

74

LF

j

74

22

6

6

22

75

VT

k

75

23

7

7

23

76

FF

l

76

24

8

8

24

77

CR

m

77

25

9

9

25

78

SO

n

78

26

:

:

26

79

SI

o

79

27

;

;

27

80

DLE

p

80

28

<

<

28

81

DC1

q

81

29

=

=

29

82

DC2

r

82

30

>

>

30

83

DC3

s

83

31

?

?

31

84

DC4

t

84

32

@

@

32

85

NAK

u

85

33

A

A

33

86

SYN

v

86

34

B

B

34

87

ETB

w

87

35

C

C

35

88

CAN

x

88

36

D

D

36

89

EM

y

89

37

E

E

37

90

SUB

z

90

38

F

F

38

91

ESC

{

91

39

G

G

39

92

FS

|

92

40

H

H

40

93

GS

}

93

41

I

I

41

94

RS

~

94

42

J

J

42

95

US

DEL

95

43

K

K

43

96

FNC3

FNC3

96

44

L

L

44

97

FNC2

FNC2

97

45

M

M

45

98

SHIFT

SHIFT

98

46

N

N

46

99

Code
C

Code
C

99

47

O

O

47

100

Code
B

FNC4

Code
B

48

P

P

48

101

FNC4

Code
A

Code
A

49

Q

Q

49

102

FNC1

FNC1

FNC1

50

R

R

50

103

START
A

START
A

START
A

51

S

S

51

104

START
B

START
B

START
B

52

T

T

52

105

START
C

START
C

START
C

STOP

STOP

STOP

Code 128 checksum digit calculation

The CODE
128 checksum digit is the result of the weighted sum of the values
of each of the digits modes 103.

The steps
for calculating the check digit are as follows:

Add the
start character value(103, 104, or 105) to the running checksum.

Take
each character in the message, take its value, and multiply
it by its character position, and add the total to the running
checksum.

The checksum
digit is the result of running checksum modulo 103.

Example:to
calculate the checksum digit example :"EASESOFT1234".

String

Start
B

E

A

S

E

S

O

F

T

Start
C

12

34

Value

104

37

33

51

37

51

47

38

52

99

12

34

Weight

1

1

2

3

4

5

6

7

8

9

10

11

Sum

104

37*11=37

33*2=66

51*3=153

37*4=148

51*5=255

47*6=282

38*7=266

52*8=416

99*9=891

12*10=120

34*11=374

Summing
up the sum of each character,The sum is 104+37+66+153+148+255+268+266+416+891+120+374=3112.

3112
divides 103, the remainder is 22,so the checksum digit is 22.

STRUCTURE OF A CODE 128 BARCODE

A Code 128
barcode has the following physical structure:

Start
code, which is the code 103, 104, or 105 from the encoding table
.

Each
of the data bytes of the message, encoded with the encoding
table.

The checksum
byte, calculated as described above and encoded using the table.

Stop
character.

Termination
bar of 11.

UCC/EAN-128
SYMBOLOGY

UCC/EAN-128
only can encode numeric data using the Code 128 Character Set
C. UCC/EAN-128 starts with character C,follow FNC1 character(
102) and other data.